I was attempting to install something on my computer, and it tells me to search the folder that I want to install it. So I just put Program Files (x86) as usual. After the installation finished I went to the folder (Or, tried to) the folder doesn't exist. So I tried search around computer, and nothing. So I decided to re-install. I chose the same folder, but then I noticed that in the little browser window to pick folder, a bunch of folders appear , that don't really exist on my computer, since I have long deleted/uninstalled them.

I have my settings to see the invisible folders, but still can't find them. This is very awkward

Most programs when un-installed will leave the "program Files" folder behind. Also they tend to leave a load of crap in the registry. In regards to loosing folders that are installed, I'm not sure. Although are you installing a game?? I ask because the folders are not necessarily named as you think and it might be that the installer is putting the new install in the old folders. Find and open the folders that you have highlighted and see whats in them.